中国夏季降水异常空间模与副热带高压的关系

本文用1959～1994年6、7、8月全国范围47个5°×5°经纬度网格降水资料分析了夏季降水异常空间模的月际差异，并在此基础上用西太平洋副高指数及青藏高原指数#FKB#FS分析降水异常空间模与环流的关系，为检验环流指数与降水相关场的整体信度，还对8月份降水资料进行了Monte-Carlo检验。结果表明，夏季总降水异常的空间模在每一月份中并非表现得同样清楚，江淮流域与河套及华南的反相关在8月份表现得最清楚。而青藏高原中东部南北两侧的负相关在6月及8月很清楚，7月份次之。8月份西太平洋副高北界异常对江淮流域与河套及华南地区降水异常反相关的产生有很大作用。副高稳定偏北时，河套、华南易涝，江淮易旱。反之亦然。青藏高原指数#FKB#FS与逐月降水的相关分析表明，青藏高原上高压及低涡活动对高原中东部南北两侧负相关的产生有一定作用。当高压活动偏多时，北侧易旱、南侧易涝。并且6月及8月的作用较大，7月较小。另外，8月份副高活动对这一降水异常空间模的产生也有一定影响。     

用数字滤波方法进行数值模式的初始化

将数字滤波原理用于Ｔ４２Ｌ９全球谱模式的初始化。选取两个初值进行了实验。通过对模式短时间积分得到的时间序列进行滤波处理，有效地滤去了初始场中的高频重力波振荡，保留了其中有天气意义的扰动，同时对分析场的改变很小。５ｄ预报的结果说明，经过初始化后的预报较为平稳，场较为光滑。对比实验表明，绝热和非绝热初始化的效果很接近。这种方法简便有效，是一种实用的初值化方法     

植被冠层多角度遥感研究进展

综述了近年来关于植被冠层多角度遥感研究的最新成果，分别讨论了二向性反射的正向模型和参量反演问题在理论和实际应用中的新进展。分析了卫星平台多角度遥感的应用前景及面临的困难，指出了未来多角度遥感研究的新方向。     

上海自然植被的特征、分区与保护

上海地区有种子植物约134科510属919种。种子植物的分区类型共15°个,其中泛热带分布、北温带和东亚分布各占总属数的27.8%、21.6%和11.9%.地带性植被以常绿阔叶林和常绿落叶阔叶混交林为主,其中红楠群落和青冈栎群落能较好地反映中亚热带的植被和环境特征。非地带性植被以潮间带植被和水生植被为主。上海自然植被的类型和分布规律反映了本区地处中亚热带向北亚热带过渡地带的气候特征以及濒江临海的环境特点。同时其现状也表明了上海的自然植被处于不断增长的压力之下所发生的变化,因此亟需加以保护。上海的植被区划可分为隶属于北亚热带常绿落叶阔叶林地带的河口沙洲植被区,碟缘高地植被区和东北淀泖低地植被区,以及隶属于中亚热带常绿阔叶林地带的西南丘陵、低地植被区等。     

RELATIONSHIP OF ECO-ENVIONMENTAL CHANGE WITH NATURAL EROSION AND ARTIFICIALLY ACCELERATED EROSION

Ｆｏｒｌｏｎｇｔｉｍｅ,ｔｈｅｐｒｏｂｌｅｍａｂｏｕｔｎａｔｕｒａｌｅｒｏｓｉｏｎａｎｄａｒｔｉｆｉｃｉａｌｌｙａｃｃｅｌｅｒａｔｅｄｅｒｏｓｉｏｎｉｓｉｎｄｉｓｐｕｔｅ.ＨｉｓｔｏｒｉｃａｌｇｅｏｇｒａｐｈｅｒｓｃｏｎｓｉｄｅｒｔｈａｔｈｕｍａｎｉｎｄｕｃｅｄｅｃｏｅｎｖｉｒｏｎｍｅｎｔａｌｄｅｓｔｒｕｃｔｉｏｎｉｓａｃｃｏｕｎｔａｂｌｅｆｏｒｔｈｅｓｅｖｅｒｅｓｏｉｌｅｒｏｓｉｏｎａｎｄｅｃｏｅｎｖｉｒｏｎｍｅｎｔｄｅｔｅｒｉｏｒａｔｉｏｎｏｎＬｏｅｓｓＰｌａｔｅａｕ[7,8].Ｓｏｍｅｇｅｏｌｏｇ…     

Fully normalized spherical cap harmonics: application to the analysis of sea-level data from TOPEX/POSEIDON and ERS-1

We introduce two sets of fully normalized harmonics for the spectral analysis of functions defined on a spherical cap. The harmonics are the products of Fourier functions and the fully normalized associated Legendre functions of non-integer degree. Using Sturm-Liouville theory for boundary-value problems, we present two convenient and stable formulae for computing the zeros of the associated Legendre functions that form two sets of orthogonal functions. Formulae for the stable numerical evaluation of the fully normalized associated Legendre functions of non-integer degree that avoid the gamma function are also derived. The result from the expansions of sea-level anomaly from altimetry into Set 2 fully normalized cap harmonics shows fast convergence of the series, and the degree variances decay rapidly without aliasing effects. The zero-degree coefficients (Set 2) of sea-level anomaly from TOPEX/ POSEIDON (T/P) and ERS-1 indicate an El Niño event during 1993 January-1993 July, and a La Niño event during 1993 November-1994 July, although the ERS-1 result is less obvious. Ocean circulations over the South China Sea and the Kuroshio area are clearly identified with the low-degree expansions of sea-surface topography (SST) from T/P and ERS-1. A cold-core eddy of 4° in diameter centred at 17.5°N, 118 E was detected with the expansion of SST from T/P cycle 47, and a property of the cap harmonics is used to compute this eddy's kinetic energy. The kinetic energy is at a low in winter and high in summer, and its variation seems to be periodic with an amplitude of 0.4 m² S^-2.     

A model for the Am (Km) planetary geomagnetic activity index and application to prediction

We studied the existence of dynamical stochastic relations in the evolution of the am index. A first analysis of the autocorrelation functions showed evidence of several seasonalities. We first used linear (ARMA) models, and it was found that these do not account for the whole internal dynamics of the data series. We then used various non-linear models to provide a better fit to reality. The forecast performances of the non-linear models are not significantly different from those of the linear model. We give a tentative explanation for the failure of the non-linear predictions. Finally, ARCH models were used in order to take into account the fact that the confidence interval for the predicted value depends on past observations.     

航空短波红外分光谱遥感技术直接寻找油气藏的有效性及应用实例

采用航空短波红外分光谱遥感技术，在新疆准噶尔盆地和塔里木盆地某些油气区，进行直接寻找油气资源的试验研究后发现，油气区含油岩系，油气藏上方盖层土壤的光谱在２３００和２３５０ｎｍ波段具有双吸收特征。     

红外,紫外及荧光分析在有机包裹体研究中的应用

本文利用红外，紫外及荧光分析方法，对岩石中吸附有机质和包裹体有机质进行了分析研究，红外分析结果表明，生油岩中的包裹体有机质有明显的石油峰，并且与吸附有机质的峰形有较大差别，紫外分析结果也表明，生油岩中两种有机质的光谱性质不一致，而非生油岩则相反，生油岩荧光光谱特征为：荧光强度大（〉４０），λｍａｘ在４５０ｎｍ左右，光谱位于蓝绿光区，演化程度属高成熟原油阶段，这些可作为评价生油潜力，演化程度的方法及     

Barotropic local instability and severe storm process

By means of barotropic model, the characteristic and initial value problems are investigated to reveal the local two-dimensional barotropic instability of the nonuniform current to the dynamic mechanism of the formation of the Yangtze-Huaihe River severe storm in July 1991. Analytical theory and numerical experiment show that (i) the unstable developing modes are chiefly the two periods of about 44 d and 10 d, which are fundamentally consistent with that of the precipitation change of the Yangtze-Huaihe River. (ii) The growth rate of the local perturbation is dominated by the meridional wave numbern = 1–5 and zonal wave numberk = 1–12, i.e. the severe storm over the Yangtze-Huaihe River results from the interaction of the systems at different latitudes and waves of different scales, (iii) The perturbation over the Yangtze-Huaihe River possesses the property of local intensification, which slowly migrates westward over the lower and middle reaches of the Yangtze-Huaihe River. (iv) The growth rate of the instability, especially the propagation velocity of the perturbation, is sensitive to the external parameters ū and α. Project supported by the National Natural Science Foundation of China.